1. Technical Field
The present invention relates to energy beam control of wave-type energy beams including electromagnetic waves, acoustical waves, and moving particles, optical computers, optical signal processing, optical signal amplification, and basic optical logic functions.
2. Background Art
The "Optical Computing Method Using Interference Fringe Components Regions" (U.S. Pat. No. 5,093,802, Hait, 1992) provides amplification by using constructive interference to remove energy from an energy-supplying beam which remains on, diverting it into an output along with energy from a modulated input beam. As a result, the amount of energy that appears in the modulated portion of the output is greater than the amount of energy in the modulated input beam.
The disadvantage of the prior method is that a portion of the energy supplying beam appears in the output all the time. This occurs because the prior art uses the most popular and well studied interference effects, such as Young's fringes, where energy appears at the location of fringe component separation, whenever any one of the input beams is on by itself. See, U.S. Pat. No. 5,093,802, State 2 of FIGS. 1 and 2, and Col. 6, lines 7-45, especially lines 36-40. However, there exist other interference phenomena which may be used to alleviate the prior art problems.
These special interference phenomena are produced whenever the geometry of the apparatus is such that energy from a plurality of beams causes destructive interference at the first location(s) where energy from the input beams appears when any one of the input beams is on by itself. Since the law of conservation of energy requires that the energy in the beams not be destroyed by the destructive interference, when an out-of-phase beam is on, the energy must appear somewhere else. Depending on the geometry of beam superposition, the energy will be reflected, or diverted to a position adjacent to the first location(s), or at some angle in between. The important result is that energy from the plurality of beams is actually diverted away from the first location(s) where destructive interference occurs and on to a second location where constructive interference occurs, outside of the area where at least one input beam appears in the absence of interference.
In the most elementary examples, having only two input beams, two types of special interference are manifest. With the first type, neither of the input beams contribute energy to the second location when either one is on by itself. When both input beams are on, interference causes energy from both beams to appear at the second location.
With the second type of special interference, the first input beam contributes no energy to the second location when it is on by itself. When the second input beam comes on, interference causes energy from both input beams to appear at the second location. However, energy from the second beams beam does appear at the second location when it is on by itself.
Some embodiments and applications of the present invention is able to use either type of special interference. There are some things, however, that require one type or the other, but will not work for both types; e.g., the logical AND, discussed below.
The individual beams, in either type of special interference, actually produce images at the locations where interference takes place, even if these images are just simple spots. These images then interfere with each other.
In complex images, one or more input beams are able to produce image component area(s) that correspond to the simple examples above. The inputs are subsets of a plurality of input beams that form images. When only one beam set is on, and as a result its image is on, the energy pattern defines a set of "first" locations by the presence of energy. When at least two of the subsets are on, interference occurs between the two images, and energy from both images is removed from the first locations by destructive interference. That energy then appears at the second location(s) because of constructive interference. The second locations lie outside of the area where the first locations are.
Holograms, especially but not exclusively computer-generated holograms, like other pictures, are made up of individual pixels. From each pixel comes a group of rays that eventually combine to produce the wave-front reconstructed holographic image. As a result, each spot on the image is produced by a group of rays from the hologram. The rays constitute a set of beams. When a whole set or beams are modulated in concert, the image it produces, and the complex interference that occurs between it and other images is also modulated. Interference between such images, made by subsets of all input beams, are also able to be used to produce the special interference phenomena used by the present invention.
The important difference between these special interference phenomena and Young's fringes used in the prior art is that energy from at least one of the input beam sets, which appears at the second location(s), appears while interference is occurring, and does not appear at that location(s) in the absence of interference. On the other hand, the input beams used in Young's fringes do appear at that second location(s) in the absence of interference, when any of those beams are on by themselves.
These special phenomena are analog in nature, in that the amount of energy that appears at the second location(s) is proportional to the amount of energy in the two input beams or images. The energy appearing at the second location(s) has been diverted from the first location(s).
If one input is held constant, and a second input(s) is increased, the amount of energy contributed to the second location(s) from the first input(s) reaches a limit where the addition of more energy in the second input(s) is unable to cause more energy from the first input(s) to appear at the second location(s).
The phenomena may be utilized in digital energy circuits through the use of discrete levels for modulating the input beams, to establish discrete states of the interference images, having discrete amounts of energy in their component parts.
The present invention uses these heretofore-unused phenomena to produce a basic means and method of energy beam control that has direct application in optical computing, photonic signal processing, acoustic imaging, and moving particle imaging.
An additional difference between the present invention and nearly all of the prior art is that the present invention operates at the full speed of whatever energy form is being used. For example, if light is the energy form used, the present invention operates completely at the speed of light, as does the invention disclosed in U.S. Pat. No. 5,093,802. Any introduction of electronic, mechanical, or acousto-mechanical components only serves to limit processing speed to that of the slowest component.
U.S. Pat. No. 5,239,173, by Yang, is an excellent example of an attempt to amalgamate light with slow components, while also using Young's fringes. Yang states, in col. 2 lines 17 and 18, "A mechanical or electro-optical shutter is provided at each slit so as to turn the light ON and OFF," and restates this in his claim 1, col. 5 line 23. Optical sensors or detectors are also used as noted at col. 3, lines 58 & 58, and col. 5 lines 61 & 62. These also limit the speed of operation to that of the slow electronic sensors.
Electrons are simply too slow. Photons are much faster, and that is why the present invention should be practiced without utilizing any components that require changes in the energy type used, although the present invention is able to use one embodiment for acoustical waves for detecting or generating acoustical images, while another embodiment is able to use light for processing those images after they have been converted to optical signals.
Yang also uses Young's fringes. This is evident by the description of his first three figures at col. 2 line 58 to col. 3 line 58 which describes double slit diffraction, a common term of art for Young-type interference fringes. The fact that his AND device requires "two detectors working cooperatively" (col. 3 lines 54 to 57) shows this to be the case. The "null" as well as the "constructive interference" at two different positions must be sensed in order to detect a state where both input beams are on so that his AND is actually the result of ANDing two sensor outputs, and is not a direct result of using interference alone.
As a result of these inherent problems of the prior art, the whole conceptual process of the present invention is geared to the interaction of components without requiring conversion from one energy form to another, and to the use of special interference, which is able to produce effects that Young's fringes do not.